Load responsive wheel suspension for vehicles



March 30, 1965 G. E. MATHER 3,175,836

LOAD RESPONSIVE WHEEL SUSPENSION FOR VEHICLES Original Filed Nov. 26,1957 2 Sheets-Sheet 1 gk 3'. w to m .2 g Q 0 F cu (0 S2 i A O 9 x.INVENTOR GlenE.Mothsr ATTORNEY March 30, 1965 G. E. MATHER 3,175,836

LOAD RESPONSIVE WHEEL SUSPENSION FOR VEHICLES 2 Sheets-Sheet 2 OriginalFiled Nov. 26, 1957 Glen E. Mother United States Patent 3,175,836 LOADRESPONSIWE WHEEL SUSPENSION FUR VEHICLES Glenn E. Mather, Logansport,1nd, assigncr to Rockwell- Standard Corporation, Coraepolis, Pan, acorporation of Fennsylvania Original application Nov. 26, 1257, Ser. No.698,981, now

Patent No. 3,080,177, dated Mar. 5, 1963. Divided and this applicationMay 29, 192, Ser. No. 198,552

16 Claims. (Cl. 280-6) This invention relates to vehicle wheelsuspension apparatus for motor vehicles and more particularly to wheelsuspension assemblies which include self-actuating fluid pressureoperated levelizers.

Hydraulic levelizers are generally known and a variety of types havebeen designed to level the body frame under varying static and dynamicloads. Such devices have been widely used in buses and delivery truckswhere the load changes constantly as shown, for example, in US. PatentNo. 2,687,311 issued August 24, 1954. Hydraulic levelizers may be eitherfully automatic, self-actuating or controlled by the vehicle operator.

A primary object of this invention resides in the provision for vehiclesof a novel combination of coil spring wheel suspension and levelizer inone assembly which is fully automatic and thus does not required theattention of the driver.

A further object of the invention resides in the provision of a springsuspension comprising a novel arrangement of support control armspivotally mounted on the vehicle frame.

An additional object of the invention resides in the provision of anovel wheel suspension assembly including two support control armspivotally connected to a frame member of a vehicle, one of the controlarms having a spring connected thereto, the spring being shiftable in aline transverse to the axis of the coil spring to change the effectiveforce applied by the spring to the control arm whereby the frame ismaintained in a desired position in relation to the wheel axle.

A still further object resides in the provision of a novel vehiclecombination including the vehicle frame supported by ground engagingwheels mounted on transverse axle assemblies with an automaticlevelizing suspension mechanism on each wheel which substantiallyimmediately individually adjusts the level of the frame portion adjacenteach wheel relative to the position of the wheel when ever the relativepositions change because of changed static or dynamic loads.

Still another object of the present invention resides in the provisionof improved self-actuating levelizers for suspension assemblies, whichinclude a valve which is closed or opened by movement of one of thesuspension arms to actuate a fluid pressure motor to move the point ofconnection of the main load-carrying spring to a part of the suspension.

It is another object of the present invention to provide in an improvedself-actuating hydraulic levelizer system for vehicle suspensionassemblies, a valve which is closed and opened by means of a solenoidactuated by a two-way switch connected to one of the control arms of thelevelizer.

It is a further object of the present invention to provide improvedcombined suspension and levelizing mechanisms which are adapted for usein the suspension of either front or rear wheels and which, when used tosuspend the rear axle, permit the use of conventional rear endassemblies without torque tubes or radius arms found in other levelizingunits since the load is transmitted directly by the spring suspension tothe frame of the vehicle.

It is a further object of the present invention to provide improvedself'actuating fluid operated levelizing sys- 3,175,836 Patented Mar.30, 1965 terns which eliminate excessive body sway when the vehicle istaken around a curve and reduce or eliminate the brake dive at the frontend of the vehicle when the brakes are applied.

It is an additional object of the present invention to provide improvedwheel suspension systems which comprise inexpensive and easy tomanufacture parts which are simply and quickly assembled and installedand which require a minimum of maintenance.

It is also an object of the present invention to provide improved fluidactuated fully automatic levelizing suspension systems of simpleconstruction which require only low or moderate constant operatingpressures.

Further novel features and other objects of this inven tion will becomeapparent from the following detailed description, discussion and theappended claims taken in conjunction with the accompanying drawingsshowing preferred structures and embodiment, in which:

FIGURE 1 is a top plan view of a motor vehicle frame supported bysuspension and levelizing mechanism in accord with a preferredembodiment of this invention;

FIGURE 2 is an enlarged front elevation partially broken away andshowing the front wheel suspension and levelizing assembly;

FIGURE 2A is a fragmentary view partly in section showing the outer endmounting of the coil spring of FIGURE 2, as well as the pivotalconnections of the link and the piston rod of the motor with thatmounting; and

FIGURE 3 is a partial side elevation partially in section shown in rearwheel suspension and levelizing assembly.

In referring to the drawings for a detailed description of theinvention, like reference characters will refer to like partsthroughout. FIGURE 1 illustrates a motor vehicle frame 10 to which frontwheels 12 are connected by independent spring suspension assemblies 13of the present invention. Rear axle 11 which is supported by rear wheels14 is connected to the frame by a pair of spring suspension assemblies15. A power plant (not shown) is drive connected in conventional mannerthrough a ditferential 16 and axle 11 to the rear wheels 14. Thesteering linkage includes the usual transverse tie rod 18.

FIGURE 2, to which detailed reference will now be made, illustrates apreferred embodiment of the suspension and levelizing mechanism of theinvention as applied to steerable front wheels.

Indicated at 89 is a transverse vehicle frame member of generallyU-shaped cross-section on one end of which is secured by welding orother suitable means an upper mounting bracket $0 to which is pivotallysecured as at 92 an upper bifurcated control arm 94. The outer end ofthe control arm 94 is pivotally secured by a suitable ball and socketjoint 96 to the upper end of a steering knuckle 98 having a spindle 100for rotatably supporting a front wheel. The lower end of the steeringknuckle 98 is connected by means of a ball and socket joint 1112 to oneend of a lower control arm 104 pivotally secured at its opposite end asat 106 to a lower mounting bracket 108 secured by bolts 110 over theopen underside of the frame member 89.

A bracket 112, welded to the upper control arm 94, extends downwardlytherefrom and pivotally supports as at 114 one end of a link 116 ofconstant length. The opposite end of link 116 is pivotally connected at118 to a coil spring retainer cup 120 connected as by helical retainergrooves 121 to one end of a tension coil spring 122 housed by the framemember 39. The opposite end of the coil spring is secured adjacent theapproximate centerline of the vehicle to a bracket 124 welded in theframe member, the spring end being held in place by means of a bolt 126.

.With the axle 11 is a link Also fastened to the pivot pin 118 as withinthe bifurcated end of spring retainer cup 120 is the lower end of thepiston rod 128 of a fluid pressure motor 130 pivotally mounted at 92 toupper mounting bracket 90. Fluid conduits 132 and 133 lead from chambersat opposite sides of the power piston within motor 130 to a solenoidoperated valve 134' connected in turn to a suitable source of pressureand to exhaust. The valve 134, which is of conventional construction, isspring biased to a neutral or cut-off position in which both conduits132 and 133 are isolated from the source of pressure and from exhaustand is moved in opposite directions to connect conduit 132 to pressureand conduit 133 to exhaust or vice versa by respective solenoids 135 and136. Solenoids 135 and 136 in turn are actuated by a double pole switch137 mounted on the frame member 89 and actuated by a member 138 movablewith the lower control arm 104. The asesmbly is completed by a shockabsorber 139 connected between the upper and lower control arms 94 and104.

The rocking of the control arms 94 and 104 beyond a predetermined rangecaused either by an increase or a decrease in load operates the switch137 to actuate one of the solenoids 135 or 136 to energize the fluidmotor 131 to thereby change the relative position of pivot point 118thereby lengthening or shortening the effective moment arm acting on theupper control arm 94.

FIGURE 3 illustrates an embodiment of the levelizer and suspensionassembly for connecting the rear axle 11 to a longitudinal vehicle framemember 141.

Pivotally mounted as at 142 in a bracket 143 rigid 144 the upper end ofwhich is pivotally connected as at 145 to one end of a triangular uppercontrol arm 146. The opposite end of the control arm 146 is pivotallysupported a at 147 on a bracket .148 rigid with the frame member 141. Alink 152 corresponding to the link member 116 of FIGURE 2 is pivotallysupported as at 150 on the lower vertex of the triangular control arm.The opposite end of the link 152 is pivotally secured as at 154 to aretainer plug 156 secured to one end of a coil spring 158 the oppositeend of which is secured to a tension bracket 160 on the frame 141 by aconventional attachment assembly indicated generally at 162.

The free end of a piston rod 164 is connected to the pivot 154 on thespring retainer plug 156 and at its opposite end extends into thecylinder of a fluid pressure motor 166 which is pivotally secured by thepivot 147 to the bracket 148. The motor 166 is connected by conduits 168and 169 to a solenoid operated valve identical with the valve 134. Thevalve operated solenoids are controlled by a switch 170 connected byoperating links 172, 174 and 176 to the end of the upper control arm146.

In this embodiment of the invention lower control arm 178 also functionsas a torque rod or radius rod. Control arm 178 is pivotally connected asat 180 to a bracket 182 rigid with frame member 141 and is resilientlyconnected to the rear axle by U-bolts 186.

The rear suspension and levelizer assembly shown in FIGURE 3 operates inthe same manner as the FIGURE 2 embodiment.

in both suspensions a change in load will result in turning of a controlarm about its frame pivot, and this movement of the control arm willoperate the electric switch, 137 or 171 to actuate the solenoid valve134 to energize the fluid pressure motor (13% or 166) in the properdirection to displace the point of connection between the end of thetension spring, 122 or 153, to a position where the force exerted by thespring in the suspension changes to restore the control arm and thesuspension linkage to original equilibrium or neutral condition wherebythe height or level of the frame relative to the axle structure isrestored and maintained. Thus constant level is obtained within thesystem.

The suspension and levelizing systems of the present invention can beused either for passenger cars or for heavy duty truck applications. Inthe latter case, for example, the rapid levelizing action of the systemis effective to hold a trailer at the level of the loading dockthroughout an entire loading or unloading operation.

Illustrative of the economy of manufacture of the mem bers comprisingthe suspension levelizing mechanism of this invention the coil spring,for instance, can be made as an extension type spring of oil temperedwire functioning at very low stress which is the most economical of alltypes of manufacture. The control arms are preferably made from steelstampings. The ball and socket joints are of a well known conventionaltype. The hydraulic system is in general very simple and is operaitve atrelatively low pressures of from 200500 p.s.i.

In general, the present invention will considerably improve ridingcomfort and lessen fatigue imposed upon the driver of the vehicle overlong distances.

This is a division of my copending application Serial No. 698,981 filedNovember 26, 1957 for Levelizing Suspension, now U.S. Letters Patent No.3,080,177 issued March 5, 1963.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be Patent is:

1. In a levelizing spring suspension for a vehicle having a frame and anaxle structure, a control arm pivotally conected at opposite ends tosaid frame and the axle structure, a coil spring, means on the framesuporting one end of said spring, force transmitting means comprising arigid link pivoted at one end on said arm and at its other end to theother end of said spring, and fluid pressure means operably mountedbetween said frame and that said pivot between said link and said springhaving a control circuit containing a valve actuated by changes inrelative level of said frame and axle structure for automaticallyshifting said pivot between said link and said spring to vary theeffective force exerted by said spring on said control arm.

2. In a self-leveling suspension for a vehicle having a frame adapted tobe supported by an axle structure provided with a ground engaging wheel,upper and lower control arms flexibly connected at opposite ends to theaxle structure and frame, a coil spring, means on the frame supportingone end of said spring, a rigid link pivoted at one end to said uppercontrol arm and having at its other end a pivotal connection to saidspring, power means for automatically shifting said pivotal connectionin re-- sponse to a change in relative level between the frame and theaxle structure comprising a motor having a driven member operablyconnecting said pivotal connection and said frame, and control means forsaid power means actuated by movement of one of said control armsrelative to said frame.

3. A levelizing spring suspension for supporting a ve hicle frame on anaxle structure comprising upper and secured by Letters lower memberspivotally connected at one end to said frame, means flexibly connectingthe other ends of said members to the axle structure to permit relativevertical movement between said axle structure and said frame, a springassembly having one end connected to said frame, a link pivotallyconnecting theopposite end of said spring assembly to one of saidmembers, and means automatically responsive to changes in level betweenthe frame and said axle structure for shifting the pivotal connectionbetween said spring assembly and said link.

4. A levelizing spring suspension for supporting a vehicle frame on awheel comprising upper and lower control members pivotally connected tosaid frame, wheel axle structure flexibly connected to said members soas to permit controlled relative vertical movement between said axlestructure and said frame, a coil spring anchored at one end on saidframe, a link pivoted at opposite ends to the other end of said springand the upper control member, and means automatically responsive to achange in the angle of pivot of one of said control members in relationto the frame for shifting the point of connection of said spring to saidlink to vary the effective force of said spring in the suspension.

5. In a levelizing spring suspension for a vehicle having a frame and anaxle structure, a control arm pivotally connected at opposite ends tosaid frame and the axle structure, tension spring means, means on theframe sup porting one end of said spring means, a force transmittinglink pivoted at one end to said spring means and at its other end tosaid control arm, and power actuated means responsive to a change inrelative level of said frame and axle structure for automaticallyshifting said pivot between the spring and control arm to vary theeffective force exerted by said spring means on said control arm.

6. In a levelizing spring suspension for a vehicle having an axlestructure adapted to support a frame, a control arm pivoted at oppositeends to said frame and said axle structure, a coiled tension springhaving one end secured to the frame, a link having pivot connections tothe other end of said spring and an intermediate portion of said controlarm, and means responsive to changes in relative evel of said frame andaxle structure for automatically shifting the pivot connection of thelink to the spring for varying the effective spring force acting on saidcontrol arm.

7. An assembly for spring suspending a vehicle frame on a groundengaging wheel comprising upper and lower members pivotally mounted onsaid frame, an axle structure for said wheel operatively connected tosaid members, a spring connected at one end to said frame, a linkpivotally connected at one end to "the opposite end of said spring andat the other end to one of said members, and a fluid pressure motorpivotally supported on said frame and having a piston rod, the free endof which is pivotally connected to said opposite end of said spring.

8. In a levelizing spring suspension for a vehicle having an axlestructure adapted to support a frame, a control arm pivoted at oppositeends to said frame and said axle structure, a coil spring having one endanchored on said frame, a link having opposite end pivot connections tothe other end of said spring and said control arm, and meansautomatically responsive to changes in relative level of said frame andaxle structure for shifting the pivot connection of said link to saidspring for varying the effective spring force acting on said control armcomprising a motor pivoted on the frame on the same axis as said controlarm and having a fluid pressure responsive element connected to saidpivot between the link and the spring.

9. In the suspension defined in claim 8, said motor having a fluidpressure control circuit having a valve, and means operativelyconnecting said control arm to actuate said valve.

10. A levelizing spring suspension for supporting a vehicle frame on anaxle structure comprising upper and lower members pivotally connected atone end to said frame, means flexibly connecting the other ends of saidmembers to the axle structure to permit relative vertical movementbetween said axle structure and said frame, a spring assembly having oneend connected to said frame, a link pivotally connecting the oppositeend of said spring assembly to the upper member, and means automaticallyresponsive to changes in level between the frame and said d axlestructure for shifting the pivotal connection between said springassembly and said link comprising a reversible fluid pressure motorpivoted on the frame coaxially with said upper member and having adownwardly extending pressure responsive element connected to the pivotbetween the link and said spring assembly.

11. In the suspension defined in claim 10, said motor having a fluidpressure control circuit containing a reversing valve, and meansconnected to one of said members for actuating said valve.

12. in the suspension defined in claim 11, said valve being a solenoidvalve, and said valve actuating means comprising a switch operated bysaid one member and electrically connected to said valve.

13. A levelizing spring suspension for mounting a vehicle frame on atransversely extending rear axle assembly having a housing supported byground engaging wheels comprising upper and lower longitudinallyextending members pivotally connected at one end to said frame, meansflexibly connecting the other ends of said members to the rear axlehousing to permit relative vertical movement between said axle assemblyand said frame, a longitudinally extending coil spring assembly havingone end mounted on said frame, a rigid link pivotally connecting theopposite end of said spring assembly to the upper of said supportmembers, the pivotal connection between the link and spring assemblylying adjacent and below the frame pivot of said upper member, and meansautomatically responsive to changes in level between the frame and saidaxle assembly for vertically shifting the pivotal connection betweensaid spring assembly and said link comprising a fluid pressure motorpivoted on the frame coaxially of said upper member and having a motiontransmitting connection to said pivotal connection between the springassembly and link, said motor having a control circuit containing areversing valve operably connected to said upper member.

14. In the levelizing suspension defined in claim 13, said membersextending oppositely with respect to said axle housing.

15. A levelizing spring suspension for mounting each side of the frontend of a vehicle frame on independent wheel axle structure comprisingupper and lower generally parallel members pivotally connected at theirinner ends to said frame and extending transversely between said frameand said axle structure, means flexibly connecting the other ends ofsaid members to said axle structure to permit controlled relativevertical movement between said axle structure and said frame, a coilspring assembly having one end anchored to said frame and ex tendingtransversely toward said axle structure, a rigid link pivotallyconnecting the outer end of said spring assembly to said upper member,the pivotal connection between the link and spring assembly lyingvertically between said members, and means automatically responsive tochanges in level between the frame and said axle structure for shiftingthe pivotal connection between said spring assembly and said linkcomprising a fluid pressure motor pivoted on the frame coaxially of saidupper member and operably connected to said pivotal connection betweenthe spring assembly and said links, said motor having a control circuitcontaining a reversing valve operably connected to said lower member.

16. In the levelizing suspension defined in claim 15, a shock absorberconnected directly between said members.

References Cited in the file of this patent UNITED STATES PATENTS1,880,343 Dunn Oct. 4, 1932 2,351,291 Ross June 13, 1944 2,782,049 PerasFeb. 19, 1957 2,882,041 Gustafson Apr. 14, 1959

1. IN A LEVELIZING SPRING SUSPENSION FOR A VEHICLE HAVING A FRAME AND ANAXLE STRUCTURE, A CONTROL ARM PIVOTALLY CONNECTED AT OPPOSITE ENDS TOSAID FRAME AND THE AXLE STRUCTURE, A COIL SPRING, MEANS ON THE FRAMESUPORTING ONE END OF SAID SPRING, FORCE TRANSMITTING MEANS COMPRISING ARIGID LINK PIVOTED AT ONE END ON SAID ARM AND AT ITS OTHER END TO THEOTHER END OF SAID SPRING, AND FLUID PRESSURE MEANS OPERABLY MOUNTEDBETWEEN SAID FRAME AND THAT SAID PIVOT BETWEEN SAID LINK AND SAID SPRINGHAVING A CONTROL CONTAINING A VALVE ACTUATED BY CHANGES IN RELATIVELEVEL OF SAID FRAME AND AXLE STRUCTURE FOR AUTOMATICALLY SHIFTING SAIDPIVOT BETWEEN SAID LINK AND